Memory loss is one of the main complaints among healthy elders. Recent evidence suggests that hormonal changes accompanying menopause may partly account for memory-loss in aging women and that these memory effects can be tempered by the use of hormone replacement therapy (HRT). The mechanism of these cognitive benefits remains unclear. Two major neuropsychological hypotheses used to account for cognitive aging phenomena suggest that either frontal lobe deficits or medial temporal lobe deficits may be involved in the HRT memory effects. The current project will explore whether HRT memory enhancement is better characterized as secondary to a change in frontal lobe, as opposed to medial temporal lobe, function. In addition to examining the effects of HRT on memory, the proposed studies will also investigate normal age- associated memory impairment. Specifically, healthy postmenopausal women drawn from a representative community sample who have undergone long-term HRT and age-matched controls who have never used HRT will be compared to younger premenopausal women on a recognition memory task. To dissociate better the neural mechanisms by which HRT modulates memory function, event- related brain potentials (ERPs) will be recorded from 64 scalp sites during the memory task. Further, neuropsychological measures thought to tap frontal and medial temporal lobe function will be collected and correlated with behavioral and electrophysiological indices of memory as convergent evidence for the dissociation between frontal and medial temporal lobe involvement. Overall, this work will serve as a means to better elucidate the type of memory changes associated with HRT and aging and to provide an initial examination of brain-behavior associations related to the memory effects reported in HRT-using postmenopausal women.